Of the five corium creations, only Cherobyl's has escaped its containment. This is statement is a bit too definitive, because it simply isn't known yet how bad

Of the five corium creations, only Cherobyl's has escaped its containment. This is statement is a bit too definitive, because it simply isn't known yet how bad the breach is at Fukushima Daiichi No. 2 - from muon radiography it certainly seems to have breached the primary (steel) containment.